Which ones?
Paul was mentoring Timothy so the letters were addressed to him to encourage him. These are pastoral letters. Timothy was young, not married, and had no children, so he did not meet the requirements for bishop per Paul's list that he included in 1 Tim. 3. Timothy's role during this period was to teach. You have no biblical basis for your statement.
By that statement, Paul, himself, did not meet the qualifications of being a Bishop, since he was unmarried and had no children.
Why was Timothy told the criteria to select bishops, and told to lay hands on them, if he did not have the right to lay hands on them? To clear things up here, laying hands on did not mean to pray over. It meant to ordain another. Paul clearly commanded Timothy to ordain bishops. Who ordains bishops aside from other Bishops and Apostles?
And biblical basis is not needed, otherwise, I could just as easily say you have no biblical basis for your canon, since the canon was not inspired by God.
See, we KNOW Timothy was martyred in the 80s AD from the same source that told us that Paul was beheaded. Timothy was preaching on the celebration of the Resurrection, which was brought such a large gathering that it filled the street. The pagans were trying to have their own parade, and when Timothy refused to vacate the street to allow them to celebrate their pagan festival, the angry pagans dragged him off in anger and stoned him.
He was serving as a Bishop at that time. As to young, that is a relative term. Timothy was young, for a bishop.See, Timothy had previous experience with the Apostles and even with Christ Himself, having been, by the same source, one of the seventy disciples sent out by Christ.
Timothy was maybe 20 at the time of the sending of the 70, and at the time he was made Bishop, he was in his 30s, which IS young for a Bishop, if it were not for his previous experience, first under his mother and grandmother, and then under Christ, and then under the tutelage of the Apostle Paul.
Since none of the things I am stating here contradict Scripture, there is no problem EXCEPT that you don't accept any extra-scriptural information as relevant, ridding you of the necessary background, context, and history surrounding the writing of Scripture, which is crucial to understanding the message.